Multicontact thermal-control apparatus



Nov. 21, 1939. w. B. MULLIN MULTICONTACT THERMAL-CONTROL APPARATUS Filed Oct.

2 Sheets-Sheet l INVENTOR, WilliamB. Mullin.

:BYQDan/id CS. ATTORNEY.

Nov. 21, 1939. w. B. MULLIN 2,180,643

MULTICONTACT- THERMAL-CONTROL APPARATUS Filed Oct. 1, 1958 2 Sheets-Sheet 2 F h n 7 i @13 I -12 I f I 5 I l Fiq. 7

INVENTQR, WilliamBMullin. w 1

AT TORNEY Patented Nov. 21, 1939 MULTICONTACT THERMAL- CONTROL APPARATUS William B. Mullin, Seattle, Wash.

Application October 1, 1938, Serial No. 232,788

1 Claim.

My invention relates to improvements in multicontact, thermal-control apparatus, more especially designed for the automatic control of electrical heating units or plants, and has for an object to provide local, graduated, automatic, temperature control for each heating unit.

Another object of my invention is to provide local, graduated, thermal control for independent fluid heating units, and thus avoid the use of expensive pipes between a central heating plant and the heating units.

Another object of my invention is to provide automatic thermal control means of greater flexibility than ordinary.

Another object of my invention is to provide distant, graduated, automatic, thermal control for a single unit or for several heating units.

Other objects of my invention will appear as the description proceeds.

I attain these and other objects of my invention with the apparatus illustrated in the accompanying two sheets of drawings, forming a part of this specification, in which Figure 1 is a side elevation of a well known design of hot water radiator fitted with my multicontact, automatic thermal-control apparatus, Fig. 2 is an end elevation of Fig. 1, Fig. 3 is a vertical, longitudinal section of a fragmentary part of Fig. 1 on the bent line 33 of Fig. 2, Fig. 4 is a front elevation of the thermal control apparatus with its cover removed, Fig. 5 is a section of Fig. 4 on the line 5-5 of Fig. 4, Fig. 6 is a front elevation of Fig. 4 on the line 6-4 of Fig. 5, Fig. 7 is a rear elevation of Fig. 4, Fig. 8 is a transverse section of Fig. 4 on the line 8-8 thereof having a part of the water chamber broken away, Fig. 9 is an edge elevation view of a segregated part of Figs. 4 and 5, Fig. 10 is a front elevation 01' a wall-fixture, distantcontrol box having a part of its cover broken away, and Fig. 11 is a diagram of the electric wiring used in my apparatus.

Similar characters refer to similar parts in the several views. Certain parts are broken away to show other parts hidden thereby.

With more particular reference to designated parts: The hot water radiator I is the ordinary structure of this kind with my particular apparatus attached. The valve and pipe connection 8 is for connection with a drain, used when emptying the radiator. The tank 9 is connected by pipe It with the upper part of the radiator, has an open top. not shown, may be at a greater distance above the radiator than shown and is used for pressure relief and when filling the radiator with water. Pipe ll connects the lower part of the radiator with the lower part of the thermal controlwater box l2, its upper end being engaged in the tapped hole ll entering the lower end of chamber l2 of water boxl2. The pipe 5 l3 connects the upper part of the radiator with the upper part of the water box i2 being engaged in the tapped hole l3 entering the chamber l2. The thermometer I4 is mounted in the pipe Hi the lower end of which is engaged in the tapped 10 hole M entering the top of the chamber l2.

The relay transformer box i5 is disposed beneath the water box l2 with which it is connected by pipe l9 which is extended into a hole in the top of the transformer box and into hole 15.

l9 in the bottom wall of the water box which does not enter the chamber l2 The sleeve I6 is threaded on its exterior and tapped and is connected with the lower end of radiator 1 at its inner end while its outer end is engaged in a 20 tapped hole in wiring box I1. Pipe [8 is extended into a hole in the top of box I! and into a hole in the bottom of transformer box l5. The construction provides for wires to be extended through the pipe l8 from the box I! into the box I5 and from the box I5 into the hole l9, thence through holes 3| and 22 into. a chamber beneath the cover 22 The electric heating element 20 has the threaded shank 2| engaged in the tapped interior of the sleeve l6 and extends into the chamber of the radiator 1. Its terminal wires enter chamber I! of box I! and are extended through a wall thereof as shown at 50 and 5| for connection with a switch, not shown, to connect with an electric service circuit.

On the front wall of the box l2 are disposed the four thermostats 23, 25, 21 and 29, normally flat against the box, and fastened at their upper ends by the cap screws 24, 26, 28 and 30, respectively, extended through holes in the thermostats into tapped holes in the box wall. These thermostats are spaced and parallel and similar. On their outer surfaces at their lower ends are fastened the insulating washers 23, 25?, 2'! and 29" respectively.

Plate 22, made of electric insulating material, is of the same size and shape as the box l2 and disposed forward thereof, spaced therefrom by the sleeves 22 and fastened in place by screws 60 22 extended through the plate 22 and said sleeves and engaged in tapped holes in the box l2, being retained opposite to the box l2. Fastened transversely on the lower part of the plate 22 is the bus-bar 4|. The four spring contact strips 33, 34, 35 and 36 are disposed parallel with each other and fastened to the plate 22, longitudinally thereof, spaced apart and from the said plate, and retained in place by the cap screws 31, 38, 39 and 40 respectively extended through holes in the upper ends of the strips, through sleeves-one of which is shown at 59 in Fig. 5 and engaged in tapped holes in the plate 22, respectively opposite the thermostats 23, 25, 2'! and 29, and all having their lower ends normally contacting the bus-bar 4i.

Near the middle of each of the contact strips 33, 34, 35 and 36 is a tapped hole opposite the insulating washers 23 25, 2F and 29 respectively, and fastened on the inner side of each of the said strips is a nut, one of which is designated 68 in Fig. 8, to reinforce the said tapped holes in the strips. The cap screws 45, 48, 4'11 and 48 are engaged in said tapped holes in the strips 33, 34, 35, and 36, respectively, and extended through the same and through holes 422 in the plate 22 to proximity with the insulated washers 23 25 2! and 29 respectively. The holes 22 are larger in diameter than are said screws. The end of the screw 45 is normally closely adjacent the washer 23 the end of the screw 46 is spaced farther from the washer 25 than is the screw 45 from washer 23, the end of the screw 47 is spaced farther from the Washer 277 than is the screw 46 from washer 25 and the end of the screw 48 is spaced farther from the washer 29 than is the screw 41 from washer 271*, as shown in Fig. 8. Each of said screws has a set nut thereon on top of the strip in which it is screwed,

one of the same being designated by 84 in Fig. 8.

A stud 43 having a threaded end is screwed into a tapped hole in the transverse center of the plate 22 and in a longitudinal hole in its outer end is monted the shaft 44 having the annular groove 44* therein. A screw 43? enters a tapped radial hole in the stud 43 and engages the groove 44 to retain the shaft 44 in operative position in the stud. The outer end of the shaft 44 is threaded at 44 and the central portion of the said shaft is enlarged at 44. The switch contact arm -42 has a hole in one end through which is extended the shaft 44 and the said arm is fastened to the shaft against the inner end of the enlargement 44 and the switch arm is free to oscillate on the stud 43 and contact any one of the cap screw heads 31, 38, 39 and 40, separately, or be disposed in a position out of contact with all of them. The solid-line position of the contact arm 42 shown in Figs. 4 and 5 makes electrical contact with the screw head 48, and in its dotted-line position at 42' it contacts with the screw head 3 while in its dotted-line position at 42" it is out of contact with all of the said screw heads. The stud 43 passes between the strips 34 and 35 the opposite edges of which are notched, not shown, to avoid contact between the said stripsand stud. A cover 22 is placed over the plate 22 and box l2, and apparatus thereon, and has an opening, larger than the shaft enlargement 44 through which the said shaft enlargement is extended. Cover 22 is retained in place by screws through the same and engaged in tapped holes in box l2.

On the outer end of the shaft 44 is attached the porcelain handle 44 having the pointer 44". In order that this handle may be removably attached in a manner which provides for the oscillation of the shaft 44 thereby, the following construction is shown: Within a chamber opening from the inner end of the handle 44 is extended the tapped sleeve 44 which is adapted for screwing on to the threaded end 44 of the shaft 44" and has its outer end fastened to the flat spring 44 the outer end of which is fastened to the handle 44. A small short stud 44 is fastened to the outer end of the shaft 44 and is extendable into an opening in the inner end of the handle. The sleeve 44 i longer than the stud and, when engaging the handle with the shaft, the handle is revolved to screw the sleeve on to the shaft end 44 till the handle contacts the end of the stud when the handle is pulled outward against the reaction of the spring 44 to allow further revolution of the handle to fully engage the sleeve on the shaft. Then the handle is turned to bring its said opening in alignment with the stud when it is engaged therewith by moving the handle inward. The handle is now engaged with the shaft for oscillating the shaft therewith. To disengage the handle from the shaft, the opposite of the above operations is followed. No novelty is claimed for the above handle construction at this time. Between the cover 22 and the handle 44 on the shaft 44 is placed the washer 22 of electric insulation and large enough to fully cover the said hole in the cover through which the shaft is extended. The above described construction provides for the attachment of the handle 44 to the shaft 44, 44 when the cover 22 is in its illustrated position, for the oscillation of the switch contact arm 42 by the handle 44 between its solid-line position and its dotted-line position at 42", shown in Fig. 4, and for the removal of the handle from the said shaft when desired. On the cover 22 in Fig. 2 is shown an arcuate arrangement of the numbers 0, 120, 140, 160 and 180. When the handle pointer 44 is set in the direction of the said 0 the switch contact arm 42 is in its position shown at 42" in Fig. 4, out of contact, when the handle pointer is set in the direction of the said the contact arm is in electrical contact with the screw head 31, when the said pointer indicates the said number the contact arm contacts the screw head 38, when the pointer is in the direction of the said number the contact arm is on the screw head 39 and when the pointer is set in the direction of the said number the arm 42 makes electric contact with the screw head 48, as shown in solid lines in Fig. 4.

As stated, the thermostats 23, 25, 21 and 29 are similar, and when the temperature of the water in the radiator I is high enough to curve them, their lower ends simultaneously move outward, away from box l2, an equal distance. By construction, when the water in the radiator I has a temperature of 120 F. the lower ends of all of the said thermostat move from the box l2 a distance suflicient to move the screw pin 45 and lift the lower end of contact strip 33 out of contact with the bus-bar 4|, but not enough to move the screw 46 and lift the strip 34 out of contact with the bus-bar, because the end of the screw 46 is set at a greater distance from the thermostat 25 than is the screw 45 from the thermostat 23. The same is true with respect to the screws 41 and 48 and for similar reasons. Thus, till the temperature of the said radiator water is raised above the temperature of 120 F. only the strip 33 will be out of contact with the bus-bar. The screw 46 is set in the strip 34 at a distance from the thermostat 25 which requires a water temperature of 140 F. in the radiator in order that the thermostat 25 curves sufiicient to raise the strip 34 clear of the bus-bar but not enough to raise the strips 35 and 36 clear thereof. The screw 41 is set at a distance above the thermostat 21 suflicient to require a temperature of the radiator water of F. in order that the thermostat may curve away from the box l2 far enough to lift the strip 35 free from contact with the bus-bar, but not far enough to raise the screw 48 and lift the strip 36 ofi of the bus-bar. And the screw 48 is set at a distance from the thermostat 29 sufiicient to require a temperature of F. of the radiator water in order that the thermostat curve enough to raise the strip 36 free from the bus-bar. Thus. when the water temperature is at a temperature of 180 F., or above, all of the said contact strips are out of contact with the bus-bar.

As shown in Figs. 1, 2 and 3, the service wires 50 and 5| enter the chamber ll of the box l1. As shown in the wiring diagram in Fig. 11, service wire 50 connects with one terminal of the primary coil 52 of a transformer disposed in box l5, not otherwise shown, and also, through wire 29, with one terminal of the electric heating element 20. The service wire 5| connects with the other terminal of the transformer primary coil 52 and, through the magnetic make and break armature 55, with the other terminal of the electric heating element 20 through the wire 20*. As shown in Figs. 4 and 5 and the wire diagram Fig. 11, the wire 51 connects the contact clamp 49 on stud 43 with one terminal of the secondary winding 53. Wire 51 passes through the hole 22 in plate 22, through the hole 3| in the wall of box l2 and into the hole l9 in said wall and thence through the pipe |9 into the transformer box [5. The other terminal of the transformer secondary coil 53 is connected with one terminal of the magnet 54, disposed in the box 5, and the other terminal of the magnet connects with the bus-bar 4| through the wire 58. The wire 58 is shown in Figs. 4 and 5 where one end is connected to the bus-bar and then it passes through the holes 22 and 3| into the pipe l9 and thence into the box |5 where the magnet 54 ishoused but not shown. From this wiring system it is clear that the electric current generated in the secondary coil of the transformer by the service current in the primary coil thereof energizes the magnet 54 and retains the circuit making and breaking armature thereof adjacent the magnet to close the circuit from the service wire 5| to the electric heating element 20, and, when the magnet is not energized, the armature may oscillate away from the magnet under the reaction of the spring 56 to its position at 55' and open this circuit thus stopping the electric current through the heating element and allowing the temperature of the water in the radiator 1 to fall. Fromthe stud 43 the circuit through the heating element 20 is continued through the shaft 44 through the switch contact arm 42, through any one of the spring strips 33, 34, 35 or 36 with which the switch arm may be connected and then through the bus-bar 4| to the wire 58. Hence, by moving the end of that particular strip, with which the switch arm is connected, from contact with the bus-bar the circuit through the magnet is opened which results in the opening of the circuit through the electric heating element 20 and, as above stated, allowing the temperature of the radiator water to fall. It is also clear that by breaking the contact of any one or more of the said strips with which the switch arm, is not connected the circuit through the heating element will not be affected, and when the switch arm 42 is out of contact with all of the screw heads 31, 38, 39 and 40 no current can flow through the magnet 54 and the circuit through the heating element may be opened by the reaction of the spring 56. From which it follows that the maximum temperature of the radiator water will be indicated in degrees Fahrenheit by the number to which the handle points as shown in Fig. 2, excepting when the handle points to 0 the radiator water will tend to fall in temperature to that of the surrounding air. And, excepting when the switch handle points to 0, the temperature of the radiator water will be automatically raised to the degree indicated by the scale number to which the switch handle points after it has fallen below the same, because the curved ends of the thermostats straighten as the temperature of the water falls and the contact strips may return to contact the bus-bar and close the circuit through the electric heating element.

The above description of my means for using separate heating units has been confined to the employment of local control. However, there is a simple way of applying distant control means to my heating units which will now be described.

Fig. 10 is a front elevation of a Wall box containing the distant control switch in which the base 66, of electric insulating material, has the switch arm 42 mounted thereon for oscillation and the switch blocks 31, 38 39 and 4|! fastened to the base in arcuate disposition around the pivot of the switch arm the outer end of which may contact each block in turn. The switch arm is shown in solid lines contacting switch block 40, in dotted lines at 42* contacting switch block 31 and also in dotted lines at 42 out of contact with the switch blocks. Ears 61, 61, having screw holes therein, are fastened to the switch base to provide means for attaching the switch box to a wall or the like. Through the hole 66 in the base are passed the wire 51,

which is connected with the switch contact arm 42, and the cable 6| containing four insulated wires 62, 63, 64 and 65 which are connected with the switch blocks 31*, 38'}, 39 and 4|) respectively. The box cover 68 is fastened to the switch base by screws and has a hole in its top through which the switch arm pivot, not shown, is extended and which is larger'than said pivot in order not to contact the cover with the pivot. Over this hole in the cover and around the said pivot is placed the insulation washer 10. Switch handle 69 is connected with the said handle and pivot to revolve the pivot and switch arm, to which the pivot is fastened. Handle 69 is made of porcelain and connected to the' switch arm pivot in the same way as above described with reference to the engagement of the handle 44 and the shaft 44 in order that it may be disengaged and removed to provide for the removal of the cover 68. By referring to Fig. 11 it may be seen that wire 51, shown in dotted lines, from the distant control switch arm 40, connects with the wire 5'1 and thus with the local control switch arm 42, and the wires 62, 63, 64 and 65 connect the screw caps 31, 38, 39 and 40, respectively, which are used as contact blocks, with the contact blocks 31*, 38, 39 and 40 of the distant control switch. With this arrangement, when the distant control switch arm 42 is in its position at 42 out of contact with all of the switch blocks, the local-control switch arm 42 may be used as though the said distant control switch were not connected; also, when the local switch arm 42 is in its position at 42", out of contact with all of the switch blocks or screw heads, the distant-control switch arm 4-2 may be used to completely control the setting of the apparatus for particular maximum temperatures. The

5 wires 62, 63, 64 and 65 are shown in dotted lines in Fig. 11. The part of the cover 68 having the scale similar to that shown at 22 in Fig. 2 is included in the portion of which has been broken away.

The number of the thermostats used and the particular setting of the screws 45, 46, H and.

48, shown in Fig. 8, are for the benefit of the description and may be varied to suit cond1= tions and preferences.

Several, otherwise separate heating units of the kind described, may be controlled as a group locally or at a distance by the simple expedient of connecting the electric heating elements of the several radiators in series relation.

It is now clear that the above-described apparatus makes easily possible the separate or group control, locally or at a distance, of otherwise independent iiuid heating units, disposed as desired, of a character adapted for automatic, maximum heat regulation.

Also, it is clear that the distant control features shown and described are not an essential part of the equipment for local control.

As stated above, a radiator of conventional shape and design is shown in the drawings for the purpose of this description, but I also have in mind especially designed radiators provided with flat surfaces suitable for mounting the thermostats directly thereon thus eliminating the Water box l2 and its connecting pipes [HI and it.

For similar reasons the electric heating element 20 is shown disposed within the radiator chamber. There are in my mind other kinds of electrical heating elements suitable for the objects of my invention yet adapted for attachment externally to radiators.

The simple bi-metal, fiat-bar thermostats shown are well suited for the manner of use described, but I have in mind other shapes and forms of thermostats, such as those of the sylphon and disc types containing a volatile liquid or operable in other ways by temperature variations, which are useful in the operation of automatically controlled electric heating apparatus.

These variations from the shapes and forms described are within the purposes and means of obtaining the objects for which my invention is intended.

Having thus disclosed my invention, what I claim as new therein and desire to secure by Letters Patent is,

In combination, a radiator structure having a chamber adapted to retain a fluid heating medium, an electric heating element disposed in said chamber, a plurality of bar-shape thermostats fastened at one end flat against a metallic wall exposed to heat from any fluid in said chamber adapted to be curved outward from said wall thereby, said metalic wall adapted to have the temperature of any fluid within said chamber, a plate of electric insulation, a plurality of spring circuit-breaking contact strips each disposed flatwise opposite one of said thermostats spaced therefrom fastened at one end to said insulation plate, screws adjustably engaged in said contact strips extended toward said thermostats spaced therefrom at varying distances, electric insulation disposed between said screws and said thermostats to insulate said screws from electric contact with said thermostats, a bus-bar fastened on said plate disposed for electric contact by the free ends of said spring contact strips, a manually operable switch contact arm mounted for oscillation on said plate to connect electrically with each and none of said contact strips in turn, and means to establish a service electric current through said electric heating element operable when said switch arm electrically connects with one of said contact strips then in contact with said bus-bar, unoperable when said thermostats curve and one pushes said one contact strip out of electric contact with said bus-bar and again operable when said thermostats straighten and said one spring contact strip may return to contact said bus-bar.

WILLIAM B. MULLIN. 

